(1) Field of the Invention
The present invention relates to an axial divergent section slot nozzle for use with a jet engine which allows a flow of ambient air by which an exhaust plume and thrust from the nozzle may be tailored.
(2) Prior Art
There are many convergent/divergent (C/D) exhaust nozzles for gas turbine engines that are disclosed in the literature and that are utilized on jet and turbojet engines for changing the throat configuration of the nozzle in order to improve engine performance during certain modes of operation. This is particularly the case in aircraft that are powered by gas turbine engines with augmentors. The exhaust nozzle may be configured in a two or three dimensional configuration with or without the capability of vectoring the exhaust gases. The purpose of the vectoring nozzle is to effectuate directional change of or reversing thrust to brake the aircraft.
For many years now, engineers and scientists have worked to design and produce gas turbine engines that are capable of short take-off and vertical landing (STOVL) operation. Also well known is that the exhaust nozzle may include positional flaps that are articulated to provide vectoring capabilities. Alternatively, the entire engine exhaust nozzle may be articulated by rotatable interconnecting ducts similar to what has been used in the Russian YAK-141 aircraft, manufactured by Yakovlevin Aircraft, in order to produce vectoring capabilities.
U.S. Pat. No. 5,797,544 to Ward illustrates a compact axisymmetrical C/D exhaust nozzle which may be utilized on a gas turbine engine for a short take-off and vertical landing aircraft and mechanisms for synchronizing the flaps and guiding the combined pressure balancing piston and synchronizing ring.
U.S. Pat. No. 4,440,347 to Madden et al. illustrates a variable area nozzle having the upstream ends of the flaps pivotally connected to an axially translatable unison ring. Apparatus is associated with the flaps to cause the flaps to rotate as the unison ring is translated to vary the area of the nozzle. The unison ring includes a balance surface fixed relative thereto which is subject to a net pressure load in the downstream direction thereby reducing the force which an actuator must exert to move the unison ring or to hold the unison ring in fixed position.
U.S. Pat. No. 5,285,637 to Barcza relates to a seal centering and restraining device for positioning the seals between the divergent flaps of a vectoring C/D nozzle. The device includes a restraint bar that spans between two adjacent divergent flaps and is pivotally attached to the air side of a seal and slidably secured by sliders to tracks on the adjacent divergent flaps, thereby sandwiching the adjacent divergent flaps between the seal and sliders. A positioning linkage connecting the two adjacent divergent flaps centers the seal at all nozzle operating conditions.
Despite the existence of these convergent/divergent nozzles, there remains a need for nozzle designs which improve performance.